Various cameras capable of automatic focus adjustment are known, whereby a shutter release operation causes travelling of a movable member for range finding as well as enabling an automatic setting of an objective in accordance with the result of the range finding, prior to actual shutter release, i.e., exposure operation. Such cameras are provided with a focus memory device which enables focus memory photographing with a focus condition which has been automatically adjusted at any time prior to a shutter release operation. As generally the range finding is effected with respect to a relatively small center region of a scene being aimed at through a viewfinder, the focus memory device is extremely useful where a photographer intends to take a photograph with a main object arranged at a marginal region of a picture and with the same object being in focus. Particularly, in such a case, the focus memory device is actuated with the main object being aimed at the center of the viewfinder image field, and then the direction of the camera is changed such that the main object can be disposed at a marginal region of the viewfinder image field, after which a shutter release operation is carried out.
One example of prior art focus memory devices of the above described type is disclosed in Japanese magazine "Photographic Industries", December 1978, at pages 70 to 74. With this prior art focus memory device, manipulation of a focus memory operating member causes travelling of a movable member so that range finding is effected while an objective is automatically set to focus on an aimed object in accordance with a range finding operation. The movable member is adapted to release a shutter at a final stroke of its travel, but is arrested by an arresting member prior to reaching the position for the release of the shutter. When a shutter release member is operated thereafter, the movable member is released from the arresting member to thereby travel for the final stroke, so that the shutter is released to effect an exposure. However, this focus memory device is disadvantageous in that it requires a large force for driving the movable member because the movable member, once arrested by the arresting member to stop travelling, must release the shutter after restarting travelling within a relatively short stroke. Thus, the durability of the components, particularly the movable member and the arresting member which is engaged by the movable member travelling under the large driving force, is poor.